Dirt

Throwing dirt to signify contempt

2 Samuel 16:13 See also Nahum 3:6

So David and his men proceeded along the road as Shimei went along the ridge of the hill opposite him. As Shimei went, he yelled curses, threw stones, and flung dust at David.

Bathing to remove dirt

1 Peter 3:21

And this water symbolizes the baptism that now saves you also — not the removal of dirt from the body, but the pledge of a clear conscience toward God — through the resurrection of Jesus Christ,

Comparative use of dirt to emphasise abundance

Zechariah 9:3

Tyre has built herself a fortress; she has heaped up silver like dust, and gold like the dirt of the streets.

Metaphorical use of filth to represent sin

Isaiah 4:4 See also Proverbs 30:11–14; Isaiah 28:8; James 1:21; Revelation 17:4

when the Lord has washed away the filth of the daughters of Zion and cleansed the bloodstains from the heart of Jerusalem by a spirit of judgment and a spirit of fire.

Refuse indicating worthlessness

1 Corinthians 4:13 See also 2 Kings 9:37; Psalm 83:10; Isaiah 5:25; Jeremiah 8:2, Jeremiah 9:22, Jeremiah 16:4, Jeremiah 25:33; Lamentations 3:45; Philippians 3:8–9

when we are slandered, we answer gently. Up to this moment we have become the scum of the earth, the refuse of the world.